Australia will face New Zealand in Sydney on October 15, opening the 2026 Rugby League World Cup.
Gold Coast captain Tino Fa'asuamaleaui has chosen Australia and is expected to start in the middle with Queensland teammate Patrick Carrigan.
The pair started together for Kevin Walters and the Kangaroos during last year's Ashes tour of the United Kingdom.
News Corp reported that Walters had confirmed Fa'asuamaleaui's decision.
"I've had chats with Tino. He is playing for Australia," Walters said per the report.
Fa'asuamaleaui had also been eligible for Samoa, which he has represented previously.
International Rugby League rules allow a player to represent only one Tier 1 nation in their career, but permit annual switches between eligible Tier 2 nations.
Cameron Murray is favoured for lock, while NSW captain Isaah Yeo is another option if he passes fitness tests after playing finals with a pectoral injury.
Reuben Cotter, Lindsay Collins and Mitch Barnett are also expected to contend for places in Australia's 23-player squad.